GKN Aerospace has successfully concluded a composite manufacturing and assembly research programme using of out of autoclave (OOA) processes and materials and PI shaped woven preforms.

These technologies are among those with the potential to transform the future manufacture and assembly of large composite aero-structures - and produce the performance gains the industry seeks in the next generation of airframes.

The OOA Composite Processing Phase II programme used OOA materials to design, develop and manufacture an affordable, lightweight, blended aircraft wing box featuring integrally stiffened skins, complex contours and four different stringer shapes.

The manufacture of the parts used vacuum bag technology and the low cost tooling that becomes practicable when curing outside the extreme autoclave environment. The wing box was then assembled using fastener free, impregnated PI joints.

Stephen Grojean, Materials and Process Engineer, GKN Aerospace explains: “As an industry we are striving to improve airframe manufacture by reducing airframe cost and weight. To achieve these goals we are designing larger, lighter, more integrated aircraft structures.

"This programme addresses two of the major challenges we face - overcoming the limitations imposed by autoclave curing and proving effective fastener free, joining processes. The results we have achieved serve as a technology enabler allowing us to progress to next stage in composite wing structure and blended wing box manufacture.”